In machinery for construction and transportation using lubricants, for example, engines and various hydraulic devices, it is necessary to remove solid contaminants from the lubricant in order to prevent damage to the machine and to prolong the life of the lubricant. For this purpose, it has been common practice to employ a fiber filter or a centrifugal filter.
On the other hand, it is often necessary to remove gaseous contaminants in hydraulic systems to maintain the efficiency and accuracy of such devices. Conventionally, devices employing buoyancy, vacuum and centrifugal force have been employed for removing gaseous contaminants, examples of which are disclosed in U.S. Pat. No. 4,548,622.
No compact and integrated device has heretofore been known, however, which is capable of simultaneously removing both solid and gaseous contaminants from a lubricant. Such a device is particularly desirable though in the engine manufacturing industry.
Moreover, as the rotational speed and output of automobile and motorcycle engines have lately been increased, the importance of removing gaseous as well as solid contaminants has increased. Excess gaseous contaminants in engine oil can cause serious difficulties, such as excess wear of lubricated parts due to oil starvation and a deterioration of the efficiency of the hydraulic valve lifters.
On the other hand, the space available inside the engine compartment is generally not sufficient to accommodate both an oil filter and a gas separator. Hence, an integrated separator is desired, both from a standpoint of space and in terms of weight.